Formation of uniform reduced graphene oxide films on modified PET substrates using drop-casting method

In this work,uniform reduced graphene oxide（RGO） films were formed on poly-（ethylene terephthalate）（PET） substrates using a simple drop-casting method.We investigated four types of substrates：unmodified PET,polydopamine-coated PET.carboxyl-group-modified PET,and alkyl-group-modified PET.Upon water evaporation,the surface of the polydopamine-modified PET substrates can interact with the reduced graphene oxide sheets to form flattened and continuous RGO films,which exhibit a sheet resistance of 21.75 kΩ/sq at 82% transmittance.The result indicates that the properties of the surface groups determined whether uniform and flattened RGO films could be formed on the substrates.Hence,we proposed a simple and effective way to produce transparent and conductive films in which the catechol unit exhibits a great effect on the deposition of uniform RGO films on PET substrates.